Posted: Fri Jan 06, 2006 11:35 am
How if separate breeding groups are distinct?Jbuza wrote:Bgood Wrote
Why is that if DNA is stable? What is causing these variations???
I am not proposing that offspring are clones of their parents. Neither am I arguing against the known fact that individuals have unique recombination of DNA. What I have stated is that there is stable information in the DNA that causes offspring to be the same kind as the parent. Observations show this.
How does this prove DNA's stability?
What observations?
What is same kind? Is it only because they can interbreed? What if one population's variation is not it's fur coloring or even its skull to body ration, but gestation period or mating season. Then they won't mate anymore.
If I bred Chihuahua's for those which have consistently shorter gestation periods, they will no longer be able to mother a mix with another breed.
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Sorry this is incorrect, it is difficult yes, however dentition can be ascribed to a family of animals with success due to comparative analysis.Jbuza wrote:Bgood
You're correct there are more variations of teeth than there are variations of wires. Thus nullifying your analogy.
Right sorry let me rephrase it would be more difficult to identify what a dinosaur looked like based on a tooth or a few bone fragments than it would be to identify what a car looked like based on a piece of wire.
We do have full skulls of T-rex's. If we find a tooth similar to one found in this skull we can be pretty certain it belongs to a carnivorous Dinosaur.
Comparative analysis allows us to use growth patterns, nerve and blood vessel channels, shape, and size to differentiate among the different classes.
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Archosaurs are thought to be the stock from which dinosaurs arose, therefore the mistake was innocent. However a correction was made and you can see how science corrects and reevaluates itself when necessary.Jbuza wrote:Bgood
Sorry, what excerpt, and what link??
Whoops sorry it was in the flood and ark thread
Revueltosaurus skeleton unearthed at Petrified Forest upsets dinosaur tale
June 24, 2005
The animal, one ofmany creatures from the Late Triassic known only from their teeth, was thought to be an ancestor of the plant-eating ornithischian dinosaurs like Stegosaurus and Triceratops, which roamed the world millions of years later in the Jurassic and Cretaceous periods.
The fact that this presumed dinosaur, Revueltosaurus callenderi, is instead a crocodile ancestor does not merely disappoint rockhounds, who sell the abundant teeth as “dinosaur teeth,” but it also throws into question the identity of other presumed dinosaur ancestors known only from teeth, which includes all Late Triassic ornithischians outside South America.
Again this only puts into question the origin of Ornithischians, this is the scientific process.Jbuza wrote:“Because the teeth look like those we know from herbivorous ornithischians, people assigned them to the dinosaurs,” said Randall Irmis, a graduate student in the Department of Integrative Biology and the Museum of Paleontology at UC Berkeley. “We think we've shown that you can't rely on the dentition to determine what is an early dinosaur, which casts doubt on all the ornithischians from the Triassic of North America.”
//www.brightsurf.com/news/headlines/view. ... leID=20248
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No, incorrect early dinosaur teeth are hard to distinguish from archasaur teeth. Perhaps due to the fact that evolution has just started the differentiation process.Jbuza wrote:Bgood
Just how did they come to the conclusion that it was a crocodile then? Also are you saying that scientists should be infallible?
Or are you saying that they should not have corrected a mistake?
How were they able to determine that it was a crocodile tooth?
I am saying that identifying dinosaurs based on a tooth or bone are even a few bone fragments certianly isn't convincing evidence.
The lesson was not that teeth alone is inconvincing evidence.
Case in point it was the teeth alone which led them to the conclusion that they belonged to a crocodile ancestor!
The lesson is that new findings will always force scientists to adjust and refine their theories.
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Family EohippusJbuza wrote:
Are you going to tell me the name or do I ask a third time in vain?
Similar teeth does not a horse make.
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